Alarm help

[Naithen]

Hi I'm new to this site and need some help.
I have recently purchased a 53 plate partner van which was apparently ex edf and bt owned.

I was told that the van has a tracker and alarm fitted however nothings active. I pulled the panel off under steering wheel yesterday to find a tracker unit and an alarm box saying texton however there are wires loose. I'm assuming it has been disconnected. Would anyone please have any info on where i can find a diagram for the wiring or how to fix it as there is nothing online. Many thanks.